How to use CSV.filter to *filter out* rows from a CSV file

[mchavarriagam]

Sorry if this is a silly question but I haven't been able to find an answer yet.

It seems all the examples I've encountered for CSV.filter are actually doing transformations on the rows but none are filtering out any rows.

I see examples like this:

CSV.filter(in_io, out_string) do |row| row[0] = row[0].upcase row[1] *= 4 end

but not like this:

CSV.filter(in_io, out_string) do |row| // logic to determine if row should be included or excluded // return row if should be included, return nil if should be excluded? end

My attempts to getting something like that to work have not worked so far.

Did I misinterpret what CSV.filter is supposed to do, or am I missing something?

[kou]

We can't remove any rows by CSV.filter.